Question Random System Shutdowns, I’m at a loss!?

williamsgarrett868

Prominent
Dec 27, 2018
7
0
510
So this issue has been persistent ever since I ordered my new motherboard about 7 months this ago.

I had a stock HP Pavilion P6520y Desktop, but after 10 years of use parts started failing so I’ve been upgrading it.

First, the hard drive failed so I got a SSD to replace it. Then I got another stick of Ram to upgrade my 6GB of ram to 10GB ( 2, 2, 2, 4)

Then my motherboard bricked. Out of nowhere. I didn’t install a bios update or flash anything. I kept my PC on and put my monitor into sleep mode, went to sleep, then in the morning, BLAMO. My PC wouldn’t turn on. The fans would spin and lights indicating power went on but it refused to post, and I tried everything. Eventually, I just ordered a new motherboard.

The bricked mobo would never shut off randomly, just would run fans forever and not post. My new motherboard (Gigabyte GA-78LMT-USB3 R2) ran great when I first installed it. It posted, it booted into windows on my SSD, and registered the RAM as 10GB. Everything was great, but eventually (after 20 min of use) the entire PC would shut down randomly. Fans would stop, lights went off, and the monitor shut down along with the tower. It kept doing that. Sometimes it would immediately turn off right when hitting the power button to turn it on. Sometimes it took 4 hours to turn off after being turned on. It just kept turning off making it impossible to use.

After researching I came to the conclusion that the PSU had something to do with it. It was a basic 250W psu, so I replaced it with a 650W Rosewill Arc psu. The problem persisted, indicating that the PSU was not the issue. The ram clearly wasn’t the issue, I even tested individually per slot, same problem. The SSD wasn’t the issue, I swapped it out with a spare HDD I had lying around and the same issue arose. It wasn’t a CPU issue, the fans all spun and worked as well. I ruled out everything. I reset CMOS and bios, to no avail. I stumbled across a page that indicated maybe it was a power switch issue the front panel, so I troubleshooted that, and the switch is not the issue either. I unplugged the switch from the mobo and used a flathead to touch the 2 power switch pins and the PC started up, but even then still shut down.

It had to be an issue with the mobo itself I just have no clue what it is. Please help me. Is it something I can fix or is it something faulty I can’t fix that requires me to buy a new mobo.

Thank so much for all your help!!
 

williamsgarrett868

Prominent
Dec 27, 2018
7
0
510
Take the motherboard out of the case and put it on a flat surface. If you can get it to post out of the case then you probably didn't ground it correctly.
I took it out of the case and put it on a flat wooden surface. It wasn’t shutting off anymore like it did in the case so yes I’m assuming it’s some sort of grounding issue. But it did however outside the case “flutter” a bit. It would kind of hiccup like it was going to shutdown and then immediately restart. The fans would slow but not stop for like half a second and then they would spin fast again and the system would reboot.
 
Also how would I fix the grounding issue? I just put it in my case like any other old board.
Without being there it is tough to say. It could be touching a part of your case metal to metal, the standoffs were not used or installed incorrectly, etc. It is a troubleshooting step. Pull the ram sticks out and use only one at a time and restart the pc to see if there is a bad ram stick. Use only the original ram sticks as mixing them is never a good idea. I would also pull and reseat every wire connection to the motherboard and from the psu to ensure they are all seated correctly.
 

williamsgarrett868

Prominent
Dec 27, 2018
7
0
510
Without being there it is tough to say. It could be touching a part of your case metal to metal, the standoffs were not used or installed incorrectly, etc. It is a troubleshooting step. Pull the ram sticks out and use only one at a time and restart the pc to see if there is a bad ram stick. Use only the original ram sticks as mixing them is never a good idea. I would also pull and reseat every wire connection to the motherboard and from the psu to ensure they are all seated correctly.
It is not a grounding issue. I think the motherboard is just faulty at this point. Even out of the case on a flat surface it is doing the same thing, suggesting that grounding was never an issue.